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52 lines
1.7 KiB
Markdown
52 lines
1.7 KiB
Markdown
---
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slug: /en/operations/system-tables/asynchronous_metric_log
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---
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# asynchronous_metric_log
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Contains the historical values for `system.asynchronous_metrics`, which are saved once per time interval (one second by default). Enabled by default.
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Columns:
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- `hostname` ([LowCardinality(String)](../../sql-reference/data-types/string.md)) — Hostname of the server executing the query.
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- `event_date` ([Date](../../sql-reference/data-types/date.md)) — Event date.
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- `event_time` ([DateTime](../../sql-reference/data-types/datetime.md)) — Event time.
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- `metric` ([String](../../sql-reference/data-types/string.md)) — Metric name.
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- `value` ([Float64](../../sql-reference/data-types/float.md)) — Metric value.
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**Example**
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``` sql
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SELECT * FROM system.asynchronous_metric_log LIMIT 3 \G
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```
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``` text
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Row 1:
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──────
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hostname: clickhouse.eu-central1.internal
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event_date: 2023-11-14
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event_time: 2023-11-14 14:39:07
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metric: AsynchronousHeavyMetricsCalculationTimeSpent
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value: 0.001
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Row 2:
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──────
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hostname: clickhouse.eu-central1.internal
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event_date: 2023-11-14
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event_time: 2023-11-14 14:39:08
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metric: AsynchronousHeavyMetricsCalculationTimeSpent
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value: 0
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Row 3:
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──────
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hostname: clickhouse.eu-central1.internal
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event_date: 2023-11-14
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event_time: 2023-11-14 14:39:09
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metric: AsynchronousHeavyMetricsCalculationTimeSpent
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value: 0
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```
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**See Also**
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- [system.asynchronous_metrics](../system-tables/asynchronous_metrics.md) — Contains metrics, calculated periodically in the background.
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- [system.metric_log](../system-tables/metric_log.md) — Contains history of metrics values from tables `system.metrics` and `system.events`, periodically flushed to disk.
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